降低Java中的图像分辨率

Question

我需要使用Java程序减小图像的大小（而不是宽度和高度）。他们为此提供了任何好的API吗？

我需要将大小从1MB减少到大约50kb-100 kb。当然，分辨率会降低，但这并不重要。

Answer 1

这是工作代码

public class ImageCompressor {
    public void compress() throws IOException {
        File infile = new File("Y:\\img\\star.jpg");
        File outfile = new File("Y:\\img\\star_compressed.jpg");

        BufferedInputStream bis = new BufferedInputStream(new FileInputStream(
                infile));
        BufferedOutputStream bos = new BufferedOutputStream(
                new FileOutputStream(outfile));

        SeekableStream s = SeekableStream.wrapInputStream(bis, true);

        RenderedOp image = JAI.create("stream", s);
        ((OpImage) image.getRendering()).setTileCache(null);

        RenderingHints qualityHints = new RenderingHints(
                RenderingHints.KEY_RENDERING,
                RenderingHints.VALUE_RENDER_QUALITY);

        RenderedOp resizedImage = JAI.create("SubsampleAverage", image, 0.9,
                0.9, qualityHints);

        JAI.create("encode", resizedImage, bos, "JPEG", null);

    }

    public static void main(String[] args) throws IOException {

        new ImageCompressor().compress();
    }
}

这段代码对我来说很棒。如果需要调整图像大小，则可以在此处更改x和y比例JAI.create("SubsampleAverage", image, xscale,yscale, qualityHints);